Embryologically, humans have 6 pairs of bilateral pharyngeal arch arteries (PAAs). In normal vascular development, the first, second, and fifth PAAs regress, leaving the third, fourth, and sixth PAAs to form the aortic arch; however, in patients with DAA, the bilateral fourth PAAs are thought to remain without normal regression or remodeling during embryonic development [9]. On the other hand, the brachiocephalic veins originate from the cardinal venous system. Usually, the proximal right anterior cardinal vein develops into the right brachiocephalic vein that drains into the superior vena cava, which is derived from the right common cardinal vein. The left brachiocephalic vein develops from the proximal left anterior cardinal vein, then both join to form the superior vena cava at the right horn of the sinus venosus, which is usually on the right [10]. The connecting vessels between the proximal right anterior cardinal vein and the proximal left anterior cardinal vein are called the transverse channels. Although the embryology of the double brachiocephalic veins is unknown, the remaining 2 channels, namely, the superior and inferior transverse channels, might be the cause [11]. To our knowledge, there have been no cases reported to date in which double brachiocephalic veins (BCV) caused airway or vessel compression. Thus, indications for performing surgery for this abnormality remain unclear. In our case, surgical repair of the DAA was only performed because it was considered that the double innominate veins would not interfere with the surgery.

In the case of a right aortic arch with an aberrant left subclavian artery, the base of the left subclavian artery can form an aneurysm, which is known as Kommerell’s diverticulum, and can cause airway compression. In the present patient, the remnant bulbous part was found on the left side of the descending aorta, which also compressed the airway from the back, and the ligamental strings of the atretic left aortic arch and the ductus arteriosus were attached to it. Surgical removal en bloc of these parts was performed to release the vascular rings and release the compression.

Although the optimal surgical timing for vascular rings has not been clearly defined, it is generally recommended to perform surgery as early as possible when any symptoms occur. The treatment is preferably performed before 6 months of age, because the development of thoracic cavity is rapidly accelerated onward it. Parcaro et al. reported that the postoperative long-term prognosis of patients with vascular rings is usually excellent, and post-surgical clinical symptoms, such as feeding intolerance and/or persistent airway symptoms can remain, depending on the severity of the stenosis by the ring and bronchomalacia. On the other hand, persistent breathing symptoms may depend on the duration until the surgical repair after the diagnosis of DAA [12]. Our present patient was noted to have stridor at 2 months of age, but tracheomalacia, bronchomalacia, and cyanosis had never been detected up to the time of DAA release at 4 months of age. It is important to explain the possibility of persisting symptoms after surgery to the patient’s parents, even though symptoms usually improve with time.

In the present case, BCVs did not require surgical intervention. Unfortunately, as there are no reports that each of BCVs passes in front and behind of the ascending aorta, we do not know what adverse events to him by not intervening for these veins. Therefore, we consider that we need to observe his general condition carefully, which are the symptoms due to compression on BPVs by ascending aorta, for example facial edema, vomiting, headache, buzzing and hearing loss. However, as these symptoms are nonspecific, we need to decide by combining with imaging methods, for example TTE, contrast-enhanced CT and cardiac catheterization. And, we have to avoid bleeding due to vascular injury at the time of cardiac catheterization and performing to thoracotomy procedure. For that as well, it is very important for us to recognize that DAA rarely complicates vascular malformations outer the heart.